Field performance evaluation of Wickman-100™ fire pump

August 8, 2005

By: Ray Ault

The Government of the NWT asked FERIC to conduct a field evaluation of the Wickman-100™ fire fighting pump. This evaluation demonstrates expected water volume and pressure for fire fighters using this pump on flat ground with a standard nozzle.

The Wickman-100 is a light-weight portable pumping unit (7.7 kg or16.8 lbs.) single stage, 2 cycle, 2.3 HP pump.

Objectives:

1. Provide nozzle pressure and water volume measurements for varying distances.
2. Determine the number of Rain Bird 70cw sprinklers that can be deployed with a Wickman-100 pump.

Methodology:

Water Volume and Distance

The evaluation occurred in a flat, short grass area at the Hinton Training Centre. Clean community water pumped into a 300 US gallon (1 135 litre) holding tank was used for the evaluation. Water for the 2 cycle Wickman-100 pump passed through a holding tank to an 8-foot (2.4 m) long 1 ½ inch diameter (38 mm) suction hose. Thirty feet (9.1 m) of 1 ½ inch lined forestry hose connected the pump to a flow meter (Figure 1). Between four and twelve lengths of 1 ½ inch forestry hose connected the flow meter to the pump discharge. A pressure gauge (Figure 2) and a standard four-aperture fire-fighting nozzle were attached to the final hose length for each measurement. The size of the nozzle orifice was changed with pressure and volume measurements taken at each setting for each length of forestry hose.

Figure 1. FMC Invalco Model 505 flow meter

Forestry hose used in the evaluation was taken off the shelf from the Hinton SRD warehouse.  A mixture of lined hose consisting of Niedner Fireline non-percolating forestry hose and Mercedes PyroBlend 780 forestry hose were used.

The pump had a 10minute warm up session prior to beginning measurements.

The first field test aimed to confirm that the specific pump being used performed within the manufacturers specifications. Forestry hose was disconnected from the end of the flow meter and the free flow water volume was recorded and compared to manufacturer specifications.

Progressively additional 100-foot lengths of hose were added to the line, and pressure readings were recorded for the hose length and nozzle orifice size.

Figure 2. Wika Instrument Corp. Model 2xx.34 process gauge with nozzle at hose end

Sprinkler Supply

A second evaluation was conducted to determine the number of Rain Bird sprinklers the Wickman-100 pump could supply and provide overlap protection for the forestry hose. 

Four hundred feet (122 m) of 1 ½ inch forestry hose was laid out with an in line water thief at each connection. (Figure 4) A Rainbird 70CW full circle sprinkler with a ¼ inch nozzle was threaded into each of the four water thieves. Pressure and volume readings were taken at the end of the fourth sprinkler. The casting distance for the third and fourth sprinklers were measured and a pressure reading was taken at the end of the fourth sprinkler. Water volume was recorded.

Results:

The pump free flow volume was recorded as 67.5 to 69.5 US gallons per minute (255.5 to 263.1 litres per minute). The manufacturer literature suggests 69 US gallons per minute (261.2 litres per minute).

The Wickman-100 pump provided pressure of 50 psi and 17 gallons per minute (64.4 litres per minute) flow when using the largest nozzle orifice (5/16 inch or 8 mm) with 1200 feet (366 m) of forestry hose.

Table 1. Hose length, nozzle diameter pressures and water volume.

* Corresponding lengths in metres are: 152 m, 183 m, 274 m, and 366 m
† Corresponding sizes in millimetres are: 3.2 mm, 4.8 mm, 6.4 mm, and 7.9 mm
‡1 litre = 0.264 US gallons

Figure 3. Nozzle water pressure using a 5/16 inch (7.9 mm) orifice with 1200 feet (366 m) of hose

Four Rain Bird 70 CW sprinklers were attached to water thieves (Figure 4) along a 400-foot (122 metre) hose lay. Pressure at the last sprinkler (#4) was 35 psi with a flow rate of 40 US gallons per minute (151.4 litres per minute). The sprinkler casting distance of the fourth and last sprinkler in line was of 13.2 meters (43.3 feet) while the third sprinkler casting was measured at 17.4 meters (57 feet). 

 
Figure 4. Water thief and Rain Bird 70 CW sprinkler

Discussion:

The results for this light-weight portable pumping unit compares favourably with other pumps in this category as listed in the CIFFC[1] pump specifications.

The model supplied started easily. The 24 to 1 fuel to oil mixture is an anomaly. The writer understands that 50:1 is the most common fuel / oil mix found on the fire line. If the GNWT has an issue with different mix ratios for pumps the manufacturer should be contacted to learn the potential consequences of using a lean mixture.

The sprinkler performance may have benefited from a loop (which provides flow in two directions) rather than the straight hose lay which was used. Similar Rain Bird sprinklers (70H) are rated at 11.5 gallons per minute (43.5 litres per minute) at 40 psi with a casting radius of 60 feet (20 meters) using a ¼ inch nozzle. The casting results from the fourth sprinkler in this evaluation are 28% lower than Rain Bird specifications found on the internet.  At 35 psi the casting distance of 43 feet is inadequate to provide overlapping spray thus leaving a portion of hose unprotected with the potential for burn through.

The pressure values recorded are approximate. The gauge values are in 5 psi increments and some slight variation occurs.